1) Field of the Invention
The present invention relates to a stick with shock-absorber.
2) Description of the Prior Art
Trekking sticks used by hikers in order to improve their stability, especially on rough terrain, by providing an additional support, are known. These sticks are adapted to cushion the impacts and vibrations generated by contact with the ground but, if necessary, they can be converted into fully rigid sticks which are more useful, for example, when climbing. Some of these sticks are constituted by two generally cylindrical coaxial members, one of which remains in contact with the ground, the second one being connected to the grip of the stick. The upper member ends with a central pin which has a smaller diameter than the lower member, so that it can be arranged partially in the lower member so as to allow mutual sliding, so that the entire assembly constitutes a single tube. A spring arranged around the central pin of the upper tube and contrasted by the edge of the lower tube acts as a cushioning device between the two members, allowing the stick to absorb the stresses with respect to the ground. The elongation of this telescopic system is determined by the stroke of the central pin with respect to the lower tube. Accordingly, a protrusion is provided at right angles on the pin and enters a slot which is shaped like an inverted L and is formed on the internal surface of the lower tube, constituting a guide for the protrusion and therefore a means for mutually locking the two telescopic members. By turning the two members that constitute the stick with respect to each other, the protrusion of the pin is moved along the horizontal part of the slot. At one end, the protrusion can slide along the longer vertical side of the L-shaped slot, thus allowing the pin to slide and enabling the shock-absorbing device; at the other end, the protrusion is locked and the shock-absorbing device is disabled.
These devices have the drawback that they are particularly heavy due to the central pin; moreover, the weight produces an unfavorable leverage for the user's wrist.
Another drawback consists of the fact that dust and moisture, by penetrating in the region where the shock-absorbing system is arranged, tend to compromise its correct operation.
Another disadvantage is constituted by the high cost due to the components and their assembly.
Other conventional trekking sticks are constituted by a single cylindrical body, which constitutes the stick itself and at the top of which a contrast disk is applied, and by a grip, which is coaxial to the stick and can slide along it. The stroke of the grip is delimited by an elastic band which is applied along a guide which is formed inside the grip and is connected, by means of a hook, to the contrast disk, to which the grip adheres when the elastic band is at rest. The grip, the elastic band and the contrast disk constitute the shock-absorbing device.
These shock-absorbing systems have the drawback that it is difficult to disable the device in the grip, because it is necessary to disengage the elastic band and apply the grip to the contrast disk, this being a troublesome and slow operation.
Another disadvantage is the fact that since the shock-absorbing member is actually an elastic band, there is no preset stroke limit, except the maximum elongation of the elastic band, with the risk of forward imbalance for the user.
Another disadvantage is the upper space occupation of the grip due to the elastic band contained therein, not to mention the fact that the debris that penetrates between the grip and the contrast disk tends to prevent the operation of the device.